Resting it against my laptop did help a little. The stylus is bigger than most pen/cils and I am constantly trying to avoid hitting the button. :/

Then again, it might also have to do with it being my left hand. A few years ago I was riding with someone in a golf cart. They turned a corner too fast and I flew out and landed on said hand. I have my hand brace hiding somewhere at home... which doesn't help me at all here.

Angling and stretching really do help along with a wrist support for when the pain is really bad. I remember when I first got a tablet how much trouble I had with hitting the buttons too. What I did to help with that was I always kept my buttons pointing up so that I could get to them if I needed while they were still out of the way. I also hold my stylus closer to the tip. It helps to use a real pen about the same size while doing other doodling or drawing to get used to the size of the stylus so that doesn't bother you as much.

The wrist exercises in the video ttallan recommended are really very good.

Someone on a different forum recommended wearing a wrist brace to bed. I can't remember where I read this, but they emphasised wearing it while you slept was more important than wearing it while you worked. Someone also said a standard leather 'rocker' wrist band worked better for them than a medical brace.

I'm lefty as well, and get pain if I draw on the tablet too long on a flat surface. Regarding avoiding hitting the button on the stylus--I had the same problem, and bought this , which comes with a buttonless grip. i use that all the time now, and it helps._________________

On most tablets you can disable the pen buttons in driver settings, or worst case you can just pull the button out entirely. Trying to dodge the buttons messed up my grip, but with it disabled everything feels fine.

I'm actually back to drawing flat. The having it at an angle was nice, but it would never stay there because of not having a stand. Doing the stretches actually help. I've had a few days now where there's been no pain with the stretches. Taking breaks helps too.

The problem I had with the buttons was mainly because I'm new to using a tablet. Now that I've had practice with it, the buttons aren't really a problem any more. My digital stuff still isn't up to the level of my traditional stuff, but it'll get there.

I can relate. I started making my webcomic using the touchpad on the laptop. That hurt like nobody's business. Bought a tablet about a month ago, but have no control over it quite yet. But what is working is going back and forth. Doing the layout with the touchpad and then doing the shading a detailing with the tablet. Works for now.